Show Up for Your 3:00 p.m. Appointment at 2:35 p.m.
What you think you're doing: Demonstrating how eager you are.
Why it doesn't work: Arriving more than five or 10 minutes ahead of time can inconvenience the person who's interviewing you, putting pressure on her to finish whatever she's working on so as not to keep you waiting.
What to do instead: Monster.com career-advice expert Mary Ellen Slayter says it's fine (even advisable) to get to the building where your interview is way before the scheduled time, but find a nearby coffee shop or just sit in your car in the parking lot while you wait. Use the extra time to review what you're going to say—and, if you're anxious, remember that the right amount of nervousness will make you an even more impressive interviewee.